1. Field of the Invention
The present invention relates to a measuring instrument for measuring a dimension of a workpiece based on a position of a detector.
2. Description of Related Art
Conventionally, measuring instruments having an arm provided with a probe (detector) and a support for supporting the arm in a manner movable in the axial direction thereof have been known, the measuring instruments measuring a dimension of a workpiece based on the position of the probe (for instance, see Japanese Utility Model Laid-Open Publication No. Hei4-45911 [FIG. 1]).
The measuring instrument shown in the Japanese Utility Model Publication has a column movable in a direction on a horizontal surface of a base, a beam supported by the column in a manner movable in perpendicular direction of the horizontal surface, a slider supported by the beam in a manner movable in a direction orthogonal to the moving direction of the column and the beam, an arm provided on the slider and a probe provided on the tip end of the arm.
When a dimension of a workpiece is measured using the measuring instrument, the column, the beam and the slider are moved to bring the probe into contact with the workpiece.
On the other hand, a measuring instrument 7 shown in FIG. 7 has been known as one of horizontal two-dimensional measuring instruments.
The measuring instrument 7 has a base 71, a column 72 vertically mounted on a horizontal surface of the base 71, a support 73 elevatably supported by the column 72, a slider 74 supported by the support 73 in a manner movable in a direction orthogonal to the moving direction of the support 73, an arm 74 provided on the slider 74 and a probe (detector: not shown) provided on the tip end of the arm 75.
When a dimension of a workpiece is measured using the measuring instrument 7, the slider 74 is moved to bring the probe into contact with the workpiece.
However, installation space of the Japanese Utility Model Laid-Open Publication No. Hei4-45911 and the measuring instrument 7 has to be twice or more as wide as the stroke of the probe (referred to detector stroke hereinafter).
For instance, when the probe of the measuring instrument 7 is moved by a detector stroke S1, the slider 74 is also moved by the detector stroke S1, so that the length of the support 73 for supporting the slider 74 has to be at least equal to the sum of the detector stroke S1 and the length X of the slider 74.
Accordingly, the installation space W7 of the measuring instrument 7 has to be 2(S1)+X or more, i.e. twice or more as wide as the detector stroke S1.
Further, in order to meet the demand for improving efficiency and speed of measurement process, reduction of the movement time for bringing the probe into and out of contact with the workpiece has been desired.